Answer:
A blackbody, or Planckian radiator, is a cavity within a heated material from which heat cannot escape. No matter what the material, the walls of the cavity exhibit a characteristic spectral emission, which is a function of its temperature.
Example:
Emission from a blackbody is temperature dependent and at high temperature, a blackbody will emit a spectrum of photon energies that span the visible range, and therefore it will appear white. The Sun is an example of a high-temperature blackbody.
Answer:
Final speed of boat + man is 1.66 m/s
Explanation:
As we know that there is no friction on the system or there is no external force on this system
So here we can use momentum conservation here

so we have
m = 85 kg
M = 135 kg
v = 4.30 m/s
now we have


Answer: C and D
Explanation: I’m pretty sure it’s C and D I got the same question but cold water let me know please, thanks!
Answer:
3360 N
Explanation:
In a first-class lever, the effort force and load force are on opposite sides of the fulcrum.
The lever is 5 m long. The load force is 1.50 m from the fulcrum, so the effort force must be 3.50 m from the fulcrum.
The torques are equal:
Fr = Fr
(1440 N) (3.5 m) = F (1.5 m)
F = 3360 N
X ray is one of the electromagnetic waves.
As per Clark Maxwell's electromagnetic theory, all the electromagnetic waves move with the velocity of light i.e c= 3×10^8 m/s
In case of electromagnetic waves,the electric field and magnetic field are perpendicular to each other as well as perpendicular to the direction of propagation.The electromagnetic waves exhibit the property of polarisation. Hence they are transverse in nature.
Hence the best statements about X- ray will be-
1- X -rays are electromagnetic waves
2-X-rays are transverse transverse waves
3- X- rays travel at the speed of light.